Marina Wheeler, a lawyer and QC, said the prime minister’s proposed new EU settlement had passed up a chance to repatriate legal powers taken by the European court of justice.
Wheeler, who is an expert in public administration, said: “Proper reform needs to address the EU legal order, in particular the jurisdictional muscle-flexing of the court of justice in Luxembourg. The new proposals do not do this. Instead, they duck the issue entirely – clearing the way for a whole new body of EU rights law.
“Now, when Britain is debating its relationship to the EU, we should state our position afresh. Here is an opportunity to restore a measure of constitutional coherence. Let us not pass it by.”
Her intervention comes as Johnson has been expressing concern that Cameron has not done enough to assert the sovereignty of the UK parliament over European law – although it had been thought that the prime minister would be able to buy him off.
Cameron has been planning to tackle the issue of an assertion of UK sovereignty by replacing the Human Rights Act and asserting the supreme court could have powers analogous to the German constitutional court. The idea of a bill to resolve the London mayor’s concerns emerged after he questioned the prime minister directly on the subject in the Commons last week.
A decision by Johnson to back Brexit would electrify the Leave campaign, which is struggling with internal disputes, and lacks a big name political figure to head the campaign. Many foreign embassies regard Johnson’s decision as critical to the outcome of the referendum.
Iain Duncan Smith, the work and pensions secretary is currently regarded as the most senior figure, but polls show that if Johnson backed leave, as many as 10% of the electorate could be swayed.
The idea of quitting the EU is also gaining support in the latest ICM poll, taken in the wake of the negative media reaction to the terms negotiated by Cameron and EU council president Donald Tusk.
It found that the two sides of the argument were locked at 50% among voters who had made up their minds – a two-point rise for Leave and a similar dip for Remain since the proposals emerged last week.
In a surprisingly downbeat message at odds with British statements on the subject, Tusk said Britain’s EU negotiations is delicate. “Let me be clear, this is a very fragile political process,” he warned. “Therefore I have decided to cancel all my obligations and will hold a number of meetings with EU leaders and with the European parliament in order to help reach an agreement.”
French president François Hollande, German chancellor Angela Merkel, Greek prime minister Alexis Tsipras, Romanian president Klaus Iohannis and Czech prime minister Bohuslav Sobotka are among those who have been slotted into his diary.
However, foreign secretary Philip Hammond, who is giving evidence to the European scrutiny committee, expressed confidence that a deal would be struck at the special EU council on 18 and 19 February.
The foreign secretary also confirmed that the agreement struck with the UK’s partners in Europe will not require change to the union’s governing treaties.
The foreign secretary claimed that while it would be “neater and tidier” to enshrine the demands in EU law, the international agreement signed when negotiations conclude will be sufficient.
“What is irreversible is the international law decision, which will be unanimously made by the 28 member states, registered by the UN as an international legal decision with treaty status and could only be reversed by an equally unanimous decision, ie a decision that the UK has concurred in,” he told MPs.
“What is being explored is options of incorporating these measures in the primary legislation of the EU through treaty change at a point in the future. We’ve always said that that would be desirable, that that would be preferable, but it is not essential in order to deliver the irreversibility.”
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